From a81efc0f6f2d9a9d90aff878a4e212fc81a176cd Mon Sep 17 00:00:00 2001
From: John Safranek <john@wolfssl.com>
Date: Wed, 18 Sep 2024 15:14:52 -0700
Subject: [PATCH] Small Stack ECC Pairwise Consistency Test

1. Update the ECC PCT to use the key's heap to allocate any buffers for
   the test. This is similar to how RSA does it.
2. Put the buffers on the stack if not using small stack option.
---
 wolfcrypt/src/ecc.c | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/wolfcrypt/src/ecc.c b/wolfcrypt/src/ecc.c
index 3d439e1cf7..e662b6e62f 100644
--- a/wolfcrypt/src/ecc.c
+++ b/wolfcrypt/src/ecc.c
@@ -10211,23 +10211,31 @@ static int _ecc_pairwise_consistency_test(ecc_key* key, WC_RNG* rng)
     }
 
     if (!err && (flags & WC_ECC_FLAG_DEC_SIGN)) {
+#ifndef WOLFSSL_SMALL_STACK
+        byte sig[MAX_ECC_BYTES + WC_SHA256_DIGEST_SIZE];
+#else
         byte* sig;
+#endif
         byte* digest;
         word32 sigLen, digestLen;
         int dynRng = 0, res = 0;
 
         sigLen = (word32)wc_ecc_sig_size(key);
         digestLen = WC_SHA256_DIGEST_SIZE;
-        sig = (byte*)XMALLOC(sigLen + digestLen, NULL, DYNAMIC_TYPE_ECC);
+#ifdef WOLFSSL_SMALL_STACK
+        sig = (byte*)XMALLOC(sigLen + digestLen, key->heap, DYNAMIC_TYPE_ECC);
         if (sig == NULL)
             return MEMORY_E;
+#endif
         digest = sig + sigLen;
 
         if (rng == NULL) {
             dynRng = 1;
-            rng = wc_rng_new(NULL, 0, NULL);
+            rng = wc_rng_new(NULL, 0, key->heap);
             if (rng == NULL) {
-                XFREE(sig, NULL, DYNAMIC_TYPE_ECC);
+#ifdef WOLFSSL_SMALL_STACK
+                XFREE(sig, key->heap, DYNAMIC_TYPE_ECC);
+#endif
                 return MEMORY_E;
             }
         }
@@ -10248,7 +10256,9 @@ static int _ecc_pairwise_consistency_test(ecc_key* key, WC_RNG* rng)
             wc_rng_free(rng);
         }
         ForceZero(sig, sigLen + digestLen);
-        XFREE(sig, NULL, DYNAMIC_TYPE_ECC);
+#ifdef WOLFSSL_SMALL_STACK
+        XFREE(sig, key->heap, DYNAMIC_TYPE_ECC);
+#endif
     }
     (void)rng;